1. Field of the Invention
Aspects of the present invention relate to a method and apparatus of providing a panoramic view, and more particularly, to a method and apparatus of correcting geometric information with respect to tilting and warping and providing a panoramic view, and an apparatus to embody the method. In this instance, the method of correcting geometric information with respect to tilting may be applicable to other methods of stitching images and acquiring an expanded image as well as providing the panoramic view.
2. Description of the Related Art
Currently, when providing a location-based service using a popularized navigation system, a portable device, a personal digital assistant (PDA), etc., more realistic image information may be provided based on a real scene with respect to a service providing area.
As an example, as shown in FIG. 1, as a vehicle moves in the direction of A→B→C, image information for showing the way needs to change from surrounding images 111 that were taken with a rotating camera on a tripod 110 at a location X into surrounding images 121 that were taken on a tripod 120 at a location Y.
However, as shown in FIG. 2, an image 220 that was taken with a camera is slightly different from an image 210 that is seen through human eyes. Namely, as it can be seen in a picture 310 of FIG. 3, a building that is in actuality standing straight up may look crooked and distorted towards the refractive direction of a camera lens. This is because distortion effects caused by the refraction of a lens are reflected in association with an optical system, when taking a photograph of a real three-dimensional object with a camera. The distorted image 220 may be corrected to have a normal image as shown in the image 210 as seen through human eyes, by transforming the distorted image 220 as shown in an image 230. An image is distorted due to lens refraction like the distorted image 220.
Also, as shown in a picture 320 of FIG. 3, a building that is in actuality standing straight up may look distorted towards its depth direction, that is, an actually identical width of an object looks different from upward and downward directions. Also, the building may look distorted towards its plane direction, that is, an object that is in actuality standing straight up looks distorted towards its left or right direction. This distortion is due to camera slant.
However, regarding tilting correction technologies, Canon Corporation is utilizing a method of checking several points of the image 220 that was taken with a camera and rotating or translating the checked points. In this instance, since a correction with respect to a depth direction is not reflected, an image which is slightly different from a real scene may be presented as a result.
Also, Microsoft Corporation is utilizing a method of reflecting depth information and applying a perspective warping transformation. In this instance, the method may have a helpful effect with respect to objects which are located at an identical distance, but when a distance is artificially changed due to imperfect depth information, an error occurs.
Also, a method of gathering and stitching images that were taken with a rotating camera on a tripod, as shown in FIG. 1, and projecting the stitched images into images in a virtual three-dimensional cylinder shape that is estimated from one optical origin, 0, as shown in FIG. 4 is utilized to provide a panoramic view.
However, conventional warping technologies for projection onto a cylinder do not accurately project images onto the cylinder. As shown in FIG. 5, as points A through F on an image plane are projected to points a through f, an edge portion is reduced toward the inside of the cylinder. Accordingly, an object on a picture looks either too short or too large in width.